MYTILUS. MUSSEL . 
109 
color, more strongly striate transversely, and covered with 
a black-brown skin which folds into raised undulations ra¬ 
diating from the beak to the margin. 
A specimen of this extremely rare shell was dredged up 
by Mr. Prideaux, in Plymouth-sound, among some coral¬ 
lines. 
3. Mytilus Crista Gall:. Cockscomb Mussel 
Barbui, pi. 11. f. 1, 2. 
Shell compressed, nigged, varying in shape, armed with 
flat concave spines, and striate with raised dot3, so as to 
be transversely nigged and strongly plaited longitudinally; 
the margin undulately plaited, with the convexities of one 
valve shutting into the concavities of the other : color fer¬ 
ruginous or dull purple, opake; inside smooth, horn-color : 
lipi both rough: hinge simple, linear, without teeth : 
length about two inches ; breadth two and a quarter. 
On the bottoms of ships, v. u. 
i 4. Mytilus edulis. Common Mussel 
Lister , pi. 362. f. 200— Pennant, pi. 66. f. 2— Da Costa , 
pi. 15. f. 5, left hand fig.— Linn. Trans, vi. pi. 18. f. 13, 
14— Donovan, pi. 128— Dorset Cat. pi. 12. f. 5, left hand fig. 
Shell oblong, very convex, somewhat falcate or incurved 
at the thicker or posterior margin, produced into a small 
angle at the anterior side, and rounded at the front margin, 
nearly smooth, covered with a dark and rather polished 
<kin, under which it is rich blue or radiate with blue and 
white: beaks pointed, close together, with the appearance 
of a prominent ridge on each side the margin down the 
posterior slope; inside whitish with a blue margin, and 
under the beak are several small tooth-like crenulations on 
the margin: length three inches ; breadth one and a half. 
Common, in vast beds. v. v. 
» §, Mytilus incurvatus. Incurved Mussel. 
List$r , pi. 362. f. 201, 202— Pennant, pi, 67- f- 1— 
Linn. Trans, viii. pi. 3. f. 7« 
Shell oblong-oval, convex, opake, nearly smooth, of an 
unpolished greyish-blue color growing darker towards the 
sides and front margin, much incurved on the posterior 
l side. 
